Metal lined metal pump barrel

ABSTRACT

This invention describes a working barrel for a deep well pumping unit. The working barrel comprises an outer steel pipe which is lined with a thin tubing of selected non-corrosive material. The inner corners of each end of the pipe is beveled. The lining is pressed outwardly against the inner surface of the pipe, and the liner and the pipe are welded together along the periphery of the outer edge of each end, to make a seal so that there will be no fluid leakage between the liner and the pipe.

Jan. 23, 1973 United States Patent 1191 Penwell s41 METAL LINED METALPUMP BARREL 3,514,128 5/1970 Hack et a1. 1 2,216,033 9/1940Hopkins........ [76] Inventor: James T. Penwell, Route No. 1, R0.

Box 45 Chelsea Okla. 74016 11/1938 Nov. 3, 1971 Appl. No.2 195,248

5/1930 Trageseretal....................

[22] Filed:

Primary Examiner-Milton Kaufman Assistant Examiner-R. i-l. LazarusAttorney-Head & Johnson Related U.S. Application DataContinuation-impart of Ser. No. 41,367, May 28, 1970, Pat. No.3,678,811.

[57] ABSTRACT This invention describes a working barrel for a deep [52]U.S. .......92/l69, 29/l56.4

well pumping unit. The working barrel comprises an outer steel pipewhich is lined with a thin tubing of [51] int.

[58] Field oiSearch..l38 l 9, 140,141, 143, 145 D,

selected non-corrosive material. The inner corners of '38/l67; 308/4 R;285/4231 1 1701 each end of the pipe is beveled. The lining is pressed551 2861 334-5; 29/1564 outwardly against the inner surface of the pipe,and

the liner and the pipe are welded together along the [56] ReferencesCited periphery of the outer edge of each end, to make a UNITED STATESPATENTS seal so that there will be no fluid leakage between the linerand the pipe.

2,693,378 11/1954 Beyer...................................285/2862,283,424 5/1942 Colwell ........................29/156.4 WL 1 Claim, 3Drawing Figures m 1 w W. 2 4 6 M a w n M w w u 2 2 I r r r I 1 .5 1/ b F7 9 VI s! 71\? sl\1 vb \i max 4711.2. 7% 1 III g ngskw :i

PATENTEUJAN 23 1975 FIG. 2

INVENTOR.

JAMES T. PENWELL K/ma #Ju/Znen,

ATTORNEYS METAL LINED METAL PUMP BARREL CROSS-REFERENCE TO RELATEDAPPLICATION This invention is a continuation-in-part of a copendingapplication Ser. No. 4l,367, filed May 28, 1970, entitled Oil Well PumpWorking Barrel now U.S. Pat.No. 3,678,811, dated July 25, 1972.

BACKGROUND OF THE INVENTION This invention is in the field of oil wellpumping devices. More particularly, it is related to the working barrelsof a sucker rod type pump.

Present day working barrels of deep well pumps, such as used for pumpingoil from an underground reservoir, commonly comprise a long rigidcylindrical metal pipe which is carefully bored and honed to form acylinder, or working barrel, into which is fitted a reciprocatingpiston. In order to prevent corrosion and pitting of this barrel, it ismade of a noncorrosive material, such as stainless steel, plated brass,monel metal, etc. Because such materials are more expensive than steel,the pump barrels are generally quite costly and means have been soughtto make them less expensive. The prior art shows instances where a thinliner has been applied to the inside of a steel working barrel. However,these, in general, have been unsatisfactory because of the imperfectfitting and leakage of fluid behind the liner, causing corrosion of theunprotected metal pipe comprising the working barrel.

It is an object of this invention to provide a working barrelconstructed of relatively inexpensive metal and to provide a liner onthe inside to fully protect the barrel from corrosion due to the fluidpassing through the pump.

SUMMARY OF THE INVENTION These weaknesses of the prior art devices andthe objectives of this invention are met by a working barrel whichcomprises a long cylindrical pipe formed of relatively inexpensivemetal, such as steel, with a thinwalled tubular liner pressed inside ofthe pipe. The inner corners of the pipe are beveled to a relativelysharp edge at the outer surface. The liner is formed in close contactwith this beveled portion, and the liner and the edge of the barrel arewelded together at the outer corners.

These and other objects of this invention and a better understanding ofthe principles and details of the invention will be evident from thefollowing description taken in conjunction with the appended drawings,in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows in elevation across-section of a working barrel and pump.

FIG. 2 is a cross-section of the working barrel taken along the line 2-2of FIG. 1.

FIG. 3 is a detail in section of the end of the working barrel showingthe manner in which the pipe and the liner are formed and weldedtogether.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,which show in FIG. 1, a borehole 30 in the earth 32. This boreholeextends from the surface down to a great depth, where it engages theporous rock of an oil reservoir, so that oil can be pumped from thebottom of the borehole to the surface. To do this, a string of tubing 16extends downward from the surface attached together by couplings 18. Atthe lower end of the tubing string is a pump, generally indicated by thenumeral 10. This comprises a working barrel 12, which is a long straightpipe with the internal surface carefully bored to be a true smoothcylinder, and finally honed to provide a smooth surface so that the pumppiston 34, with rubber seals 40, which is attached to a string of suckerrods 38, can reciprocate up and down inside the smooth internalcylindrical surface of the working barrel.

A standing valve 22 is fastened into the system at the lower end of thepump. This comprises a seat portion 42, with a sealing ball 23 whichsits on the circular seat. The sucker rod pump piston 34 is providedwith rubber cup sealing means 40 and a valve seat with a seal ball 36.The rubber cups 40 are adapted to snugly seal against the smoothinternal surface of the pump cylinder, or barrel, so that as the suckerrod 38 is lifted, the piston 34 rises, the ball 36 seals the seat in thelower end of the pump piston and any oil above the piston is liftedupward toward the surface.

As the pump moves upward, a suction below the piston draws oil from thereservoir 19 up through the standing valve 22 and fills the space 25between the standing valve and the piston. After the piston has finishedits up-stroke and starts down, the oil in the space 25 is sealed off andprevented by dropping by the seal ball 23, so that as the piston movesdown the oil now passes through the seat in the bottom of the piston,lifting the seal ball 36 as it does so, and as the piston passes downthrough the oil, the oil is now standing on top of the piston ready forthe next up-stroke of the piston, which lifts it up the tubing 16. Bythis process oil is pumped out of the reservoir 19 in the bottom of theborehole 30.

It will be readily seen that the pump barrel or cylinder 12 is a fairlyexpensive piece of equipment since it must be rigid. It must be bored asa true cylinder and must be smoothly finished or honed on the inside soas to protect the rubber seals 40 of the piston. Furthermore, becausemany of the fluids pumped from the well are of a corrosive nature, thepump barrel is generally made out of a noncorrosive material such asstainless steel, monel metal, etc., which are very expensive alloys. Inorder to avoid this large expense, this invention covers the use of aconventional steel pipe 12, with a non-corrosive metal liner 14.

The pipe is first beveled on the inside corners as shown at 26 and 26'.Next, the liner 14 which may be. of noncorrosive material, such asstainless steel, monel, etc., is placed on the inside of the pipe and ispress fitted outwardly against the barrel itself. One way of doing thisis to spin the tubing into the inside of the barrel by a rotating memberwhich is slightly oversize and, by being turned inside the tubing exertsan excessive force outward, to cause the tubing to be tightly fitted tothe inside of the barrel. Also, modern techniques of explosive formingmay be used to expand the liner 14 into the inside of the pipe 12. Theliner can be of a selected thickness, which is generally in the range ofone thirty-. second to three thirty-seconds inch, and is preferablyabout one-sixteenth inch thick.

At each end, the liner is formed outwardly against the sloping edges ofthe beveled portions 26, 26 and the liner and the pipe itself are weldedin a bead 28 at the outer edge of each end. This is shown in more detailin FIG. 3.

The barrel now comprises a rigid pipe with a tight fitting liner ofnoncorrosive material, so that the internal finishing boring and honingcan provide a smooth cylindrical pump barrel as is required. The linercovers the complete surface of the barrel so that there is nopossibility of corrosion. The welding prevents leakage of well fluidsbetween the liner and the barrel which would cause corrosion and illfitting of the liner to the barrel.

While the pump barrel is shown with an external thread on each endadapted to be fitted into couplings 18 and 20, it will be clear that afemale thread or any other type of fastening can be used. The importantdetail being that the lining itself is welded to the pipe so as toprovide a perfect seal of the space between the liner and the pipe.

As shown in FIG. 3 the outer surface of the pipe 12 is undercut belowthe root diameter of the threads 44 so as to provide clearance in thethreads of the couplings for the weld bead 28.

While the invention has been described with a certain degree ofparticularity, it is manifest that many changes may be made in thedetails of construction and the arrangement of components. It isunderstood that the invention is not to be limited to the specificembodiments set forth herein by way of exemplifying the invention, butthe invention is to be limited only by the scope of the attached claimor claims, including the full range of equivalency to which eachelementor step thereof is entitled.

What is claimed:

1. In a subterranean oil well sucker rod type of pump for use in pumpingwell fluids from a deep borehole in the earth, including a string oftubing supporting a working barrel for said pump, and a string of suckerrods to reciprocate the pump piston in said working barrel, theimprovement in said working barrel comprising:

a. a long tubular pipe of rigid metallic construction, the insideperiphery adjacent each end beveled outwardly, said pipe including malethreads at each outside end;

. a thin-walled tubular liner of stainless steel extending within saidpipe, along its entire length, the ends of said liner beveled outwardlyagainst said beveled portions adjacent each end of said pipe, said linerforming the inner periphery of said barrel for said pump piston for atleast the operative stroke of said pump;

. the ends of said pipe and said liner united, as by welding, at eachend of said barrel at a diameter intermediate the internal diameter ofsaid liner and the root diameter of said threads, to form a tight sealbetween said pipe and said liner.

1. In a subterranean oil well sucker rod type of pump for use in pumpingwell fluids from a deep borehole in the earth, including a string oftubing supporting a working barrel for said pump, and a string of suckerrods to reciprocate the pump piston in said working barrel, theimprovement in said working barrel comprising: a. a long tubular pipe ofrigid metallic construction, the inside periphery adjacent each endbeveled outwardly, said pipe including male threads at each outside end;b. a thin-walled tubular liner of stainless steel extending within saidpipe, along its entire length, the ends of said liner beveled outwardlyagainst said beveled portions adjacent each end of said pipe, said linerforming the inner periphery of said barrel for said pump piston for atleast the operative stroke of said pump; c. the ends of said pipe andsaid liner united, as by welding, at each end of said barrel at adiameter intermediate the internal diameter of said liner and the rootdiameter of said threads, to form a tight seal between said pipe andsaid liner.